Passage V
Students studied the photodecomposition (breakdown by light) of p-nitrophenol (a toxic pollutant) in wastewater. They measured the concentration of p-nitrophenol (in parts per million, ppm) in wastewater samples during exposure to various lighting conditions. Titanium dioxide (TiO2) and/or hydrogen peroxide (H2O2) were added to some samples at the start of exposure (time = 0 min). TiO2 and H2O2 speed up some photodecomposition reactions. The results of 3 sets of experiments are shown in Figures 1-3.
25. For which of the 3 figures did all of the wastewater samples studied have the same initial p-nitrophenol concentration?
Your Answer is
Correct Answer is C
Explanation
Only in figure 3, when the abscissa is 0 min, the ordinates of several lines are the same (same initial concentration)